Plastic drip hoses and drip tapes are widely used for irrigation. A drip hose or drip tape includes a hose and incorporates drip irrigation emitters. Water fed to the hose at line pressure is emitted by the emitters as a series of individual drops. Often, a number of drip hoses may be connected to and fed by a single distribution pipe with attachment ports or nipples.
Emitters may be built into a plastic irrigation hose at the time of manufacture, or may be inserted by a user. Typically, a hose is produced by means of an extrusion process by an extruder. The extruder may be provided with a die that produces a hose in its final shape. Alternatively, the extrusion process may produce an approximately flat strip or sheet. A flat sheet may be cut into individual strips. Typically, the process used to form the flat sheet may include a process, such as, for example, layering or blowing, to increase the mechanical strength of the sheet. On the other hand, a strip that is extruded directly by an extruder may not have sufficient mechanical strength to enable use for irrigation of a hose made from the strip.
A flat strip may be shaped into a hose. Typically, shaping into a hose includes bending the strip about its longitudinal axis into the shape of a hose with the desired cross section, typically circular. The edges of the strip may be welded together, or otherwise caused to adhere to one another, at a seam where the edges meet. If necessary, excess strip material may be trimmed prior to shaping into the hose.
In general, when an emitter is built into an irrigation hose at the time of manufacture, the emitter body, or a set of parts to be assembled into an emitter, is manufactured separately from the hose. The separate emitter body may then be assembled or attached, or otherwise incorporated into, the hose or a strip of hose material prior to shaping the strip into a hose. On the other hand, an emitter body formed integral to the extruded material may yield an emitter that becomes distorted during cooling or during the hose formation process. In addition, an irrigation hose thus formed may not have sufficient mechanical strength for use under typical conditions.
It is an object of the present invention to provide a single apparatus and method for continuous production of a hose with a drip irrigation emitter, with the emitter being formed from the hose material in a single production process.
Other aims and advantages of the present invention will become apparent after reading the present invention and reviewing the accompanying drawings.